EOD Primary Tumor is part of the EOD 2018 data collection system and is used to classify contiguous growth (extension) of the primary tumor within the organ of origin or its direct extension into neighboring organs. See also EOD Regional Nodes [774] and EOD Mets [776]. Effective for cases diagnosed 1/1/2018+.

EOD Primary Tumor is used to calculate Derived EOD 2018 T [785] (when applicable) and Derived Summary Stage 2018 [762]. Derivation will occur at the level of the central registry.

Note: This data item was included in Standards Volume II, Version 16; however, it was not implemented until 2018.

000	In situ, intraepithelial, noninvasive
800	No evidence of primary tumor
999	Unknown; primary tumor not stated Primary tumor cannot be assessed Not documented in patient record Death certificate only (DCO)

Note: (See the most current version of EOD (https://staging.seer.cancer.gov/) for rules and site-specific codes and coding structures.)